In the ultrasonic diagnostic device and the like capable of scanning a three-dimensional image, a device capable of driving ultrasonic transducers in a two-dimensional array by arranging an electronic circuit in an ultrasonic probe unit and performing beamforming to a portion, which is wanted to be observed, is turned into actual use. Heat radiation of such ultrasonic probe unit with high function, high output and high density mounting is an important technical problem. Since sufficient cooling cannot be performed by spontaneous cooling from a surface of a casing of the ultrasonic probe unit, a situation in which an output of an ultrasonic wave is forcedly limited occurs.
Forced cooling to allow a refrigerant to circulate through a probe cable is studied for resolving the problem in cooling. However, in the cable using a soft and flexible tube and the like, leakage of the refrigerant and failure of a pump for circulation often occur, and in such a case, cooling performance is deteriorated and there is a possibility that a surface temperature of the ultrasonic probe unit cannot be maintained within a safe range. In accordance with the regulations that the surface temperature of the ultrasonic probe unit applied to a patient cannot be higher than a certain temperature in order to prevent low temperature burn, temperature management of the ultrasonic probe unit should be certainly executed in order to prevent medical accident.
Therefore, there is the device in which a temperature sensor is embedded in the ultrasonic probe unit for detecting the temperature by the temperature sensor, thereby adjusting driving power of the ultrasonic transducer such that the temperature of the ultrasonic transducer does not become a reference temperature or higher.